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import os
import sys
import struct
import binascii
directory = "outp/"
signature = ""
ihdr_header = ""
fdat_chunk = ""
idat_chunk = ""
iend_chunk = ""
ihdrs = []
parts = []
PNG_SIGN = b"\x89\x50\x4E\x47\x0D\x0A\x1A\x0A"
def is_png(png):
"""Test if @png is valid png file by checking signature
@png can be str of the filename, a file-like object, or a bytes object.
"""
if isinstance(png, str):
with open(png, "rb") as f:
png = f.read(8)
if hasattr(png, "read"):
png = png.read(8)
return png[:8] == PNG_SIGN
def chunks(png):
"""Yield chunks from png.
@png can be a string of filename, a file-like object, or a bytes bject.
"""
if not is_png(png):
if isinstance(png, bytes):
with io.BytesIO(png) as f:
with io.BytesIO() as f2:
PIL.Image.open(f).save(f2, "PNG", optimize=True)
png = f2.getvalue()
else:
with io.BytesIO() as f2:
PIL.Image.open(png).save(f2, "PNG", optimize=True)
png = f2.getvalue()
if isinstance(png, str):
with open(png, "rb") as f:
png = f.read()
if hasattr(png, "read"):
png = png.read()
return chunks_read(png)
def make_chunk(type, data):
"""Create chunk with @type and chunk data @data.
It will calculate length and crc for you. Return bytes.
@type is str and @data is bytes.
"""
out = struct.pack("!I", len(data))
data = type.encode("latin-1") + data
a = '%08x' % (binascii.crc32(data) % (1<<32))
out += data + a.decode('hex')
return out
def chunks_read(b):
"""Parse PNG bytes into different chunks, yielding (type, data).
@type is a string of chunk type.
@data is the bytes of the chunk. Including length, type, data, and crc.
"""
i = 8
while i < len(b):
data_len, = struct.unpack("!I", b[i:i + 4])
type = b[i + 4:i + 8].decode("latin-1")
yield type, b[i:i + data_len + 12]
i += data_len + 12
if __name__ == '__main__':
i = 0
t = 0
frame_chunks = []
frames = []
for ctype, data in list(chunks('p1ng/p1ng')):
if ctype == "IHDR":
ihdr_header = data
hdr = ihdr_header
elif ctype == "acTL":
continue
elif ctype == "fcTL":
"""
"""
c = struct.unpack("!IIIIHHbb", data[12:-4])
width = 180
height = 76
if i in [11,12,13,2,9]:
width = c[0]
height = c[1]
if i in [7,13,21,22]:
width -= 1
if i == 6:
width -= 2
print c
ihdr = make_chunk("IHDR", struct.pack("!II", width + c[2], height+ c[3]) + hdr[16:-4])
ihdrs.append(ihdr)
elif ctype == "IDAT":
parts.append(("IDAT", data))
i += 1
elif ctype == "fdAT":
parts.append(("IDAT", make_chunk("IDAT", data[12:-4])))
i += 1
elif ctype == "IEND":
iend_chunk= data
break
if not os.path.exists(directory):
os.makedirs(directory)
for i in range(len(parts)):
f = open(directory + 'p1ng%d.png' % i, 'w+')
if i == 0:
ihdrs[i] = ihdr_header
f.write(PNG_SIGN + ihdrs[i] + parts[i][1] + iend_chunk)
f.close()
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